Most scrapers extract once and quit. web_harvester is a no-code Chrome extension + Python CLI that keeps running on your schedule and tells you what changed. Pick a page, tick the fields (no code, it finds them), leave it on. It pings you only when something moves: price drop, back in stock, new listing, rank or review shift, via Slack, Discord, or email. Data lands in Sheets/CSV/Excel/SQL, stacked by date. Public data, your own session, robots respected, no CAPTCHA or proxy evasion.